Women of ethnic minority groups are the most likely to suffer from unmet mental health needs including eating disorders such as binge eating and associated obesity. The long- term goal is to advance the treatment of binge eating and related problems for ethnic minority individuals by developing effective and accessible intervention programs. Despite their chronicity and severity, eating disorders largely go undetected and untreated, and women of ethnic minority groups face numerous barriers to seeking and receiving treatment. Yet no studies to date have examined the use of self-help programs to treat eating problems with ethnic minority populations, who are the groups most in need of accessible and low-cost treatment. The specific aims of the proposed project are to adapt a self-help program for Mexican American women with eating disorders and to test the effectiveness of this treatment on a community sample. Mexican Americans are one of the fastest growing populations in the United States and are at risk for binge eating and associated obesity. The first aim is to develop a Cognitive Behavior Therapy- based guided self-help program (CBT-GSH) for treatment of bulimia nervosa (BN) and binge eating disorder (BED) in Mexican American women. In the first stage of the project, focus groups and a pilot feasibility trial will be used to develop a CBT-GSH program that is culturally appropriate for Mexican values and beliefs. The second aim is to test the effectiveness of the modified CBT- GSH with a large community sample of Mexican American women with BN, BED and related binge eating problems. The study will use a between-groups (control vs. treatment) pretest-posttest design. Hypothesis #1 is that treatment with GSH (compared with no GSH) will result in a greater reduction of binge eating (primary outcome), and greater reduction in the secondary outcomes of associated eating pathology (dietary restraint, body image disturbance), attenuation of obesity, and improvement in psychological functioning. Hypothesis #2 is that treatment with GSH (compared with no GSH) will result in greater improvement or remission at 6 months follow-up. Findings from this study will contribute to advances in the treatment of BN, BED, and related binge eating problems including obesity for Mexican American women. The proposed project will provide an important step in developing effective and accessible treatment for ethnic minority individuals with eating disorders, who are groups largely, neglected in treatment trials and research and are currently underrepresented in clinic populations. Public Health Relevance: This study will be the first to develop and test an accessible, low-cost self-help treatment program for eating disorders with an ethnic minority population. This is a crucial step before dissemination on a wide scale can be implemented.